olutionary neuroscience they dream of is still in its infancy, are nonetheless al- ready preparing themselves for this fu- ture, making the appropriate adjust- ments in their everyday conversation. One afternoon recently, Paul says, he was home making dinner when Pat burst in the door, having come straight from a frustrating faculty meeting. "She said, 'Paul, don't speak to me, my sero- tonin levels have hit bottom, my brain is awash in glucocorticoids, my blood vessels are full of adrenaline, and if it weren't for my endogenous opiates I'd have driven the car into a tree on the way home. My dopamine levels need lifting. Pour me a Chardonnay, and I'll be down in a minute.' " Paul and Pat have noticed that it is not just they who talk this way-their students now talk of psychopharmacology as comfortably as of food. When their children, Mark and Anne, were very young, Pat and Paul imagined raising them according to their principles: the children would grow up understanding the world as scientists understood it, they vowed, and would speak a language very dif- ferent from that spoken by children in the past. Paul told them bedtime sto- ries about boys and girls escaping from danger by using science to solve prob- lems. He took them outside at night and showed them how, if they tilted their heads to just the right angle, so that they saw the ecliptic plane of the planets as horizontal, they could actu- ally see the planets and the earth as Copernicus described them, and feel, he told them, "at home in the solar sys- tem for the first time." Then, one eve- ning when Mark was three or four, he and Paul were sitting by the fire-they had a fire every night in Winnipeg in the winter-and Paul was teaching him to look at the flames like a physi- cist. He told him how the different col- ors in the fire indicated different tem- peratures, and how the wood turned into flame and what that meant about the conversion of energy. The boy was fascinated; but then it occurred to Paul that if he were to sit in front of a fire with a friend his age they would barely be able to talk to each other. He sud- denly worried that he and Pat were cutting their children off from the world that they belonged to. Better to wait until the world had changed, he thought. Neither Pat nor Paul feels much nos- talgia for the old words, or the words that will soon be old. They appreciate language as an extraordinary tool, prob- ably the most extraordinary tool ever de- veloped. But in the grand evolutionary scheme of things, in which humans are just one animal among many, and not always the most successful one, lan- guage looks like quite a minor phenom- enon, they feel. Animals don't have lan- guage, but they are conscious of their surroundings and, sometimes, of them- selves. Pat and Paul emphatically reject the idea that language and thought are, deeply, one: that the language we now use reflects thought's innate structure; that thought can take only the form in which we humans now know it; that there could be no thought without lan- guage. Moreover, the new is the new! It is so exciting to think about revolutions in science leading to revolutions in thought, and even in what seems, to the uninitiated, to be "raw feeling," that, by comparison, old words and old senti- ments seem dull indeed. In recent years, Paul has spent much of his time simulating neural networks on a computer in an attempt to figure out what the structure of cognition might be, ifit isn't language. Linguistic theories of how people think have al- ways seemed to him psychologically un- realistic-requiring far too sophisti- cated a capacity for logical inference, for one thing, and taking far too long, ap- plying general rules to particular cases, step by step. In order to operate at the astonishing speed at which biologi- cal creatures actually figure things out, thinking must take place along parallel, rather than serial, paths, he believes, and must be able to take immediate ad- vantage of every little fact or rule of thumb it has gleaned from experience in the past. Thinking must also be distrib- uted widely across the brain, since indi- vidual cells continually deteriorate with- out producing, most of the time, any noticeable effect. It seems to him likely that thinking takes place simultaneously along millions of different neural path- ways, each of which was formed by a particular stimulation in the past and which is, in turn, greatly or minutely al- tered by the new experience of the pres- ent. All of these pathways, connecting each neuron to millions of others, form unique patterns that together are the creature's memory. When the creature encounters something new, its brain ac- tivates the pattern that the new thing most closely resembles in order to figure out what to do-whether the new thing is a threatening predator or a philo- sophical concept. Humans being ani- mals, cogitating on the highest level is, Paul believes, just an esoteric form of ordinary perception. Sometimes Paul likes to imagine a world in which language has disap- peared altogether. We know that the two hemispheres of the brain can func- tion separately but communicate silently through the corpus callosum, he rea- sons. Presumably, it will be possible, someday, for two separate brains to be linked artificially in a similar way and to exchange thoughts infinitely faster and more clearly than they can now through the muddled, custom-clotted, serially processed medium of speech. He al- ready talks about himself and Pat as two hemispheres of the same brain. Who knows, he thinks, maybe in his chil- dren's lifetime this sort of talk will not be just a metaphor. If, someday, two brains could be joined, what would be the result? A two-selved mutant like Joe-Jim, really just a drastic version of Siamese twins, or something subtler, like one brain only more so, the pathways from one set of neurons to another fusing over time into complex and unprecedented arrange- ments? Would it work only with similar brains, already sympathetic, or, at least, both human? Or might a human some- day be joined to an animal, blending to- gether two forms of thinking as well as two heads? If so, a philosopher might after all come to know what it is like to be a bat, although, since bats can't speak, perhaps he would be able only to sense its batness without being able to de- scribe it. . THE NEW YORKER, FEBRUARY 12, 2007 69